118 

 42. Cypricercus fuscatus (Jurine). 



(PI. LIV). 



Monoculns fuscatus, Jurine, Hist, des Monocles, p. 174, PI. 19, figs. 1, 2. 

 Syn: Cypris hispida, Baird. 

 adusta, Koch. 

 fusca, Brady. 



Eucypris fuscata major, G. W. Miiller. 



Specific Characters. Female. Shell, seen laterally, oval or elliptical in 

 shape, greatest height a little in front of the middle and somewhat exceeding 

 half the length, dorsal margin rather evenly arched, ventral not at all sinuated, 

 curving somewhat upwards behind, anterior extremity broadly rounded off, 

 posterior much narrower and terminating in an obtuse corner; seen dorsally, 

 broadly ovate in outline, greatest width nearly equal to the height, anterior 

 extremity more pointed than the posterior. Valves somewhat less unequal 

 than in most of the other species, though the left one overlaps the right a 

 little along the anterior extremity, surface rather densely hairy and somewhat 

 uneven by numerous small knobs, from which the hairs arrise; inner duplica- 

 tures not very broad. Posterior antennae very slender and attenuated, natatory 

 setae extending about to the ends of the terminal claws. Spines on the outer- 

 most masticatory lobe of the maxillae coarsely denticulated in their outer part. 

 Caudal rami exceedingly slender and narrow, distal claw scarcely attaining 

 half the length of the ramus. 



Shell of a light yellowish brown hue, with a very conspicuous dark 

 chocolate brown band across the nuchal region, extending obliquely down the 

 sides of the valves to somewhat beyond the muscular spots. 



Length of adult female amounting to 1.50 mm. 



Male unknown. 



Remarks. The identity of the above described form with Jurine's Mot 

 ciilus fuscatus seems to me to be undoubitable, and I should also be much 

 inclined to believe that Cypris adusta of Koch is the same species. Brady 

 and Norman moreover quote Cypris hispida Baird as a synonym. It is the 

 largest of the Norwegian species, and may moreover be easily recognised by 

 the characteristic colour of the shell, which even in specimens for a longer 

 time preserved in alcohol is well observable. 



Occurrence. The only locality where I have hitherto met with this form, 

 is on Maerd0, outside Arendal. It occurred here very abundantly in small 

 water-holes peopled with larvae and youngs of Limnadia lenticular is. 



Distribution. Throughout Europe, North America. 



